Organic electroluminescent element

Abstract

An organic electroluminescent (EL) element has a sealed structure improved in humidity resistance. Subsequently deposited on a glass substrate of the organic EL element are components of the organic EL element, that is: a transparent electrode; an organic EL layer; and, a negative electrode. Further, the negative electrode is coated with a protection film on which a dehydrating agent is fixedly mounted using a porous sheet or a like. After that, the organic EL element has all the components sealed using a sealing member in an inert atmosphere to complete the sealed structure thereof.

What is claimed is:  
     
       1. An organic electroluminescent element comprising: 
       a positive electrode formed on a substrate;  
       an organic electroluminescent layer formed on said positive electrode, said organic electroluminescent layer comprising a hole injecting/transporting layer, a light-emitting layer, and an electron transporting layer;  
       a negative electrode formed on said organic electroluminescent layer;  
       a protection film formed on said negative electrode; and  
       a dehydrating agent which is secured to said protection film by a porous material.  
     
     
       2. The organic electroluminescent element according to  claim 1 , wherein said dehydrating agent comprises one of a chemical compound capable of keeping its solid state when taking up moisture, and a chemical compound capable of gelling when taking up moisture. 
     
     
       3. The organic electroluminescent element according to  claim 1 , further comprising: 
       a sealing member surrounding said organic electroluminescent element and secured to said substrate,  
       wherein a space defined and sealed by said substrate and said sealing member is filled with an inert gas.  
     
     
       4. The organic electroluminscent element according to  claim 1 , wherein said negative electrode is coated with said protection film in order to directly fix said dehydrating agent to said protection film by using said porous sheet. 
     
     
       5. The organic electroluminscent element according to  claim 1 , wherein said dehydrating agent is directly fixed to an upper surface of said protection film. 
     
     
       6. The organic electroluminscent element according to  claim 1 , wherein said dehydrating agent comprises one of barium oxide (BaO), calcium oxide (CaO), alumina, silica (Al 2 O 3 ), calcium sulfate (CaSO 4 ), magnesium sulfate (MgSO 4 ) and magnesium chlorate (Mg(ClO 4 )). 
     
     
       7. The organic electroluminscent element according to  claim 1 , wherein said porous material comprises one of a polyethylene resin and 4-fluoroethylene. 
     
     
       8. The organic electroluminscent element according to  claim 1 , wherein said porous material comprises a porous sheet which covers an upper portion of said dehydrating agent. 
     
     
       9. The organic electroluminscent element according to  claim 1 , wherein said porous material comprises a porous casing which surrounds said dehydrating agent. 
     
     
       10. The organic electroluminscent element according to  claim 1 , further comprising an adhesive for securing said porous material to said protection film. 
     
     
       11. The organic electroluminsecent element according to  claim 10 , wherein said adhesive is comprised of a heat-resistant material. 
     
     
       12. The organic electroluminescent element according to  claim 2 , wherein said chemical compound is formed into at least one of a powder and a film. 
     
     
       13. An organic electroluminescent element having its components arranged in a multi-layer stack in which said components comprise a positive electrode, an organic electroluminescent layer and a negative electrode, and are subsequently deposited on a substrate, and 
       wherein said organic electroluminescent layer includes a hole injecting/transporting layer, a light-emitting layer, an electron transporting layer,  
       wherein a protection film is formed on said negative electrode, a dehydrating agent with a porous surface having an adhesive portion is directly fixed to a surface of said protection film, and all said components of said organic electroluminescent element are sealed by combining a sealing member with said substrate, and  
       wherein said dehydrating agent is coated which a porous sheet, and, an adhesive provided in an end portion of said porous sheet is used to bond said porous sheet to a surface of said protection film, whereby said dehydrating agent is fixedly mounted on said surface of said protection film.  
     
     
       14. An organic electroluminescent element having its components arranged in a multi-layer stack in which said components comprise a positive electrode, an organic electroluminescent layer and a negative electrode, and are subsequently deposited on a substrate, and 
       wherein said organic electroluminescent layer includes a hole injecting/transporting layer, a light-emitting layer, an electron transporting layer, and  
       wherein a protection film is formed on said negative electrode, a dehydrating agent with a porous surface having an adhesive portion is directly fixed to a surface of said protection film, and all said components of said organic electroluminescent element are sealed by combining a sealing member with said substrate, and  
       wherein said dehydrating agent is contained in a porous casing, and adhesive provided in an end portion of said porous casing is used to fixedly bond said dehydrating agent to a surface of said protection film.  
     
     
       15. An organic electroluminescent element having its components arranged in a multi-layer stack in which said components comprise a positive electrode, an organic electroluminescent layer and a negative electrode, and are subsequently deposited on a substrate, wherein said organic electroluminescent layer includes a hole injecting/transporting layer, a light-emitting layer, an electron transporting layer, wherein: 
       a composite protection film comprising a lower layer and an upper layer is formed in a manner such that said lower layer is disposed on said negative electrode and said upper layer is disposed on said lower layer;  
       a dehydrating agent is provided over said composite protection film; and  
       all said components of said organic electroluminescent element are sealed by combining a sealing member with said substrate.  
     
     
       16. The organic electroluminescent element according to  claim 15 , wherein said lower layer of said composite protection film is made of same chemical compound or its derivative used in said electron transporting layer. 
     
     
       17. The organic electroluminescent element according to  claim 15 , wherein said upper layer of said composite protection film is made of a fluorine-based lubricant or of a diamond-like carbon. 
     
     
       18. The organic electroluminescent element according to  claim 15 , wherein a barrier metallic film is provided between said upper layer and said lower layer of said composite protection film. 
     
     
       19. The organic electroluminescent element according to  claim 15 , wherein a side surface of each of said negative electrode and said organic electroluminescent layer is coated with same material used in said upper layer of said composite protection film. 
     
     
       20. The organic electroluminescent element according to  claim 18 , wherein a side surface of each of said negative electrode, said barrier metallic film and said organic electroluminescent layer is coated with same material used in said upper layer of said composite protection film. 
     
     
       21. The organic electroluminescent element according to  claim 15 , wherein said dehydrating agent is made of a chemical compound capable of keeping its solid state even when taking up moisture, or made of a chemical compound capable of gelling when taking up moisture, and is formed into a powder or a film. 
     
     
       22. The organic electroluminescent element according to  claim 15 , wherein said dehydrating agent is coated with a porous sheet; and, an adhesive provided in an end portion of said porous sheet is used to bond said porous sheet to a surface of said upper layer of said composite protection film, whereby said dehydrating agent is fixedly mounted on said surface of said upper layer of said composite protection film. 
     
     
       23. The organic electroluminescent element according to  claim 15 , wherein said dehydrating agent is contained in a porous casing; an adhesive provided in an end portion of said porous casing is used to fixedly bond said dehydrating agent to a surface of said upper layer of said composite protection film. 
     
     
       24. The organic electroluminescent element according to  claim 18 , wherein said barrier metallic film is constructed of an aluminum film or of aluminum alloy film. 
     
     
       25. The organic electroluminescent element according to  claim 15 , wherein a space defined and sealed by both said substrate and said sealing member is filled with an inert gas.